Sign in to follow this  
The Game

Shell V Power - Unleaded

Recommended Posts

Hi

I have a 52 plate 1.0 Yaris. Its sluggish to say the least. Anyway i was wondering if i change to Shell V-Power Unleaded will it make any difference to the power? Amount of miles i can do with a full tank? Is it worth the extra money it costs.

Thanks

Share this post


Link to post
Share on other sites

for a small engine it wouldnt mke much difference performance wise , but maybe a few extra miles:rolleyes:

Share this post


Link to post
Share on other sites

What it would do is to clean the engine better than normal fuel. But I'd only use 1 or 2 tanks worth, then go back to normal. I've stopped using anything other than normal 95ron fuel in my T-Sport as there was no difference in power or mpg.

Share this post


Link to post
Share on other sites

Try an Italian tune up. They work.

Share this post


Link to post
Share on other sites

Has it been regularly serviced? A well maintained car should run fine and not be sluggish.

I would be checking the filters and plugs before wasting money on expensive fuel.

Share this post


Link to post
Share on other sites

Avanzato is spot on. The engine management system of the Yaris isn't designed to take advantage of higher octane fuels, so you will get absolutely no benefit in power or economy out of their use.

You only get the benefit with systems that detect the spark ignition "knocking" inside the engine and vary the ignition timing to get the most "advanced" ignition timing the fuel will take. Higher octane fuels will take an earlier ingition spark in the engine cycle, which is how they release their extra power and economy, but the Yaris engine management system isn't that sophisticated.

The Yaris ECU is simly fixed and assumes a single ignition timing map for a 95 RON fuel, which is the standard fuel in the UK.

I speak from experience having tried it in all my cars. So you'll get no benefit using the super unleaded all the time - however....

As Avanzato also says, the other advantage of these fuels is that they contain better cleansing agents. If you run a couple of tanks through every few months or every year, you will clean out the injectors and the valve seats and that will benefit the car, making sure you get the best out of it.

That's one of the biggest drawbacks of always using Supermarket fuel. They use the same "raw" petrol, but they don't contain all the cleansing agents that the "big brand" petrol companies put into their own fuels.

If supermarket fuel is so much cheaper locally that you use it all the time, its always good to give your car a treat now and then and give it an occasional tank of a branded fuel to give it a good clean out.

I'm lucky as my Shell station price-matches my local supermarket, so I nearly always buy the branded fuel.

I have no qualms using the odd tank of supermarket fuel, but I wouldn't use it all the time...

My brother actualy designs the engine maps that go onto the ECU chips. The first thing he asked me when I rang him last weekend about an "engine flat spot" problem on a friends car was "does he use supermarket fuel? - if he does that could be the cause of his issue...".

So its not just scaremongering, the industry actually recognises the difference between branded and supermarket fuel quality.

Share this post


Link to post
Share on other sites

:thumbsup:

I agree, higher ron fuel allows a bigger window so to speak (as they take longer to burn), hence you can advance ignition timing.

I didnt know the Yaris ECU was a 'non-learning' ECU, thanks for that :thumbsup:, any ideas if the new yaris has a learning ECU?

Your brother has a cool job :thumbsup:, I'm a software engineer but help out with tuning with my mate (he owns a dyno and shop). He tunes any car and makes custom bits of fibreglass, steel whatever.

I actually tuned and installed a supercharged on my car, a Honda S2000 - she runs at 352BHP with very little boost.

Avanzato is spot on. The engine management system of the Yaris isn't designed to take advantage of higher octane fuels, so you will get absolutely no benefit in power or economy out of their use.

You only get the benefit with systems that detect the spark ignition "knocking" inside the engine and vary the ignition timing to get the most "advanced" ignition timing the fuel will take. Higher octane fuels will take an earlier ingition spark in the engine cycle, which is how they release their extra power and economy, but the Yaris engine management system isn't that sophisticated.

The Yaris ECU is simly fixed and assumes a single ignition timing map for a 95 RON fuel, which is the standard fuel in the UK.

I speak from experience having tried it in all my cars. So you'll get no benefit using the super unleaded all the time - however....

As Avanzato also says, the other advantage of these fuels is that they contain better cleansing agents. If you run a couple of tanks through every few months or every year, you will clean out the injectors and the valve seats and that will benefit the car, making sure you get the best out of it.

That's one of the biggest drawbacks of always using Supermarket fuel. They use the same "raw" petrol, but they don't contain all the cleansing agents that the "big brand" petrol companies put into their own fuels.

If supermarket fuel is so much cheaper locally that you use it all the time, its always good to give your car a treat now and then and give it an occasional tank of a branded fuel to give it a good clean out.

I'm lucky as my Shell station price-matches my local supermarket, so I nearly always buy the branded fuel.

I have no qualms using the odd tank of supermarket fuel, but I wouldn't use it all the time...

My brother actualy designs the engine maps that go onto the ECU chips. The first thing he asked me when I rang him last weekend about an "engine flat spot" problem on a friends car was "does he use supermarket fuel? - if he does that could be the cause of his issue...".

So its not just scaremongering, the industry actually recognises the difference between branded and supermarket fuel quality.

Share this post


Link to post
Share on other sites

It may not be strickly true to say that the Yaris has a "non learning ECU"... There may well be things it does learn and adjust for from its many sensors.

What it doesn't have are "knock sensors" on the cylinder block which detect any pre-ignition and the ability to advance the ignition timing map to take advatage of different octane fuel, based on fedback from the knock sensors....

Those of us who are really old used to have cars with mechanical distributors and "points" that were driven by a cam and opened and closed to trigger the ignition spark.

You used to rotate the distributor to adjust the ignition timng and if you got it too far advanced, you could hear the engine "pinking" under load as the spark was triggered too early than the fuel could cope with....

You could buy up to four grades of petrol at the pump (2 star, 3 star, 4 star and 5 star) and it was up to you which fuel grade you wanted to pay for and how well you tuned the car to take advantage of it....

Oh - and because the fuels didn't have the cleaning additived that the branded fuels have in them now, you usd to buy "redex shots" of addative and mix them in with your fuel to have the same cleaning effect.

They were the good old days. I remember when fuel was 33p per gallon - that's 7p a litre!!! - and no I'm not a grandparent or a pensioner yet - still got 20 years to do at work......

The good old days! :-)

Share this post


Link to post
Share on other sites

It may not be strickly true to say that the Yaris has a "non learning ECU"... There may well be things it does learn and adjust for from its many sensors.

What it doesn't have are "knock sensors" on the cylinder block which detect any pre-ignition and the ability to advance the ignition timing map to take advatage of different octane fuel, based on fedback from the knock sensors....

Those of us who are really old used to have cars with mechanical distributors and "points" that were driven by a cam and opened and closed to trigger the ignition spark.

You used to rotate the distributor to adjust the ignition timng and if you got it too far advanced, you could hear the engine "pinking" under load as the spark was triggered too early than the fuel could cope with....

You could buy up to four grades of petrol at the pump (2 star, 3 star, 4 star and 5 star) and it was up to you which fuel grade you wanted to pay for and how well you tuned the car to take advantage of it....

Oh - and because the fuels didn't have the cleaning additived that the branded fuels have in them now, you usd to buy "redex shots" of addative and mix them in with your fuel to have the same cleaning effect.

They were the good old days. I remember when fuel was 33p per gallon - that's 7p a litre!!! - and no I'm not a grandparent or a pensioner yet - still got 20 years to do at work......

The good old days! :-)

I can remember buying 4 gallons of petrol for £1, - 5.5p a litre!

Those were the days!!

Share this post


Link to post
Share on other sites

I wouldn’t use V-power or any performance high octane fuel in your car. I was doing it for a while and it caused the Engine Malfunction Light to come on. I was when it was serviced that such fuels are for performance engines and are designed to be burned at very high revs. As a result the fuel wasn’t being burnt and was going out of the exhaust causing the lambada sensor to turn on the engine malfunction light. Since I’ve been putting ordinary fuel in (from reputable petroleum stations, not supermarkets, never go there) its been alright!

Share this post


Link to post
Share on other sites

The good old days! :-)

I can remember buying 4 gallons of petrol for £1, - 5.5p a litre!

I can remember my father complaining the petrol for his old James (motorbike) had gone up to `2 bob` a gallon (10p) :lol:

Share this post


Link to post
Share on other sites

The good old days! :-)

I can remember buying 4 gallons of petrol for £1, - 5.5p a litre!

I can remember my father complaining the petrol for his old James (motorbike) had gone up to `2 bob` a gallon (10p) :lol:

in 1962 you could buy 4 galls of 4 star for £1.00 and get 2pence change.this was normely given to whom served you

as a tip (no self service then).

there was a esso garage on the A11 that you put notes (£1 and £5) in slot on the pump and help your self.

Share this post


Link to post
Share on other sites

Ugh! That's quite a hike in cost from the 'old days'!

It's scary to think in a couple of decades I might be complaining that diesel used to be a cheap 114p/L compared to whatever it goes up to by then! :lol:

Personally I do something similar to what alf mentions, i.e. giving my Yaris a V-Power treat now and then :)

Mine is a diesel tho' so it's a bit different - Unlike petrol V-Power, you do notice a change in performance with diesel V-Power; My D4D idles noticeably quieter and smoother, and the engine spins up much more freely; It's great for long motorway runs! Downside is that the power I gain past 2000rpm it looses below 1500rpm, and since that's where I spend most of my time (Where I can average 65mpg! :thumbsup: ) I tend to stick with my Sainsburys diesel (Penny cheaper than anyone else, deffo better than the local Morrisons and Tesco diesel but not as nice as Shell/Esso diesels, but those are 3p more :( ) until I feel the engine bogging down and loosing power, then it's time for a motorway blast and V-Power for the next tankful! :lol:

Share this post


Link to post
Share on other sites

Thanks to everyone for the advice which made a lot of sense. I will just use it this once and then go back to regular unleaded. As yet ive only done 20 odd miles with the expensive fuel. Will see if i can do more than the usual 320 odd miles i get with a full tank.

Share this post


Link to post
Share on other sites

"They were the good old days. I remember when fuel was 33p per gallon - that's 7p a litre!!! - and no I'm not a grandparent or a pensioner yet - still got 20 years to do at work......

"

Youngster..

I remember when petrol rose from 2/3 per gallon to 2/6..# I was scandalised..

I buy standrad cooking Shell diesel.. My EGR valve is nice and clean thanks :-)

# 11.5p to 13p for the ignorant :-)

Share this post


Link to post
Share on other sites

Seen in my local Shell garage for the last couple of weeks:

"New better standard fuels coming soon......."

Be interesting to see what they are claiming is the improvement. I'm guessing just more cleansing agents.

There'll be even less need to pay extra for V-Power then......

Share this post


Link to post
Share on other sites

I tend to go to 2-3 petrol stations where they always seem to be a few pence cheaper than the next nearest.

The one nearest to me always seems to be more expensive, especially if there's a jump in Oil prices.

I've heard about some people occasionally using super unleaded to "clean out" their engine, & even a bit of petrol run though a diesel to "clear the injectors"(not recommended!)!

The first car my Dad had that could use unleaded came with the suggestion that it should be filled with 4 star every few tankfulls for some reason.

Share this post


Link to post
Share on other sites

The first car my Dad had that could use unleaded came with the suggestion that it should be filled with 4 star every few tankfulls for some reason.

That's because the older fuels contained lead to lubricate and protect the valve seats.

To cope with unleaded fuel, engine manufacturers needed to build engines with hardened valve seats and some of the early engines built during the transition period could cope with unleaded fuel most of the time but using it all the time would have caused premature valve seat wear...

Share this post


Link to post
Share on other sites

Yeah, there's a lot of misunderstanding about 'super-fuels'.

Normal super-unleaded will probably not do a great deal to help clean out the engine as it's basically high-octane unleaded.

Things like V-Power, Excelenniumium et al are also high-octane, but their selling point is that they also contain cleaning agents.

You can buy stuff in Halfords which you add to your tank during refuelling for a similar effect (Cherry Red was using that AND V-Power at one point to clean his engine out!)

I never heard of cars that benefited from using unleaded *and* 4 star tho' :unsure:

From what I knew, cars made for 4-star ran crap on unleaded (or needed super-unleaded to avoid engine damage!), and cars made for unleaded were damaged by 4-star fuel! (Well,the catalyzer anyway...?)

Edit: Ahh! I didn't realize the lead acted as a lubricant too; A bit like sulphur in diesel then :lol:

Thought it ony acted as an octane booster!

Share this post


Link to post
Share on other sites

The first car my Dad had that could use unleaded came with the suggestion that it should be filled with 4 star every few tankfulls for some reason.

That's because the older fuels contained lead to lubricate and protect the valve seats.

To cope with unleaded fuel, engine manufacturers needed to build engines with hardened valve seats and some of the early engines built during the transition period could cope with unleaded fuel most of the time but using it all the time would have caused premature valve seat wear...

I thought it might have something to do with it being a transitional engine.

Share this post


Link to post
Share on other sites

I put Half a bottle of Redex in the Yaris a few tankfulls ago, just to see if it did actually make any difference. I can honestly say it didn't but i did notice a slight change with the car when i once tried Shell V power.

It seemed to tick over more quiet, be slightly more responsive and a bit smoother. Didn't notice a huge increase in MPG though.

Could be the placebo effect?

I will try it again every few months as my Yaris seemed to like it. :thumbsup:

Share this post


Link to post
Share on other sites

Here you go...

Just announced...

"Shell Fuelsave Unleaded" and "Shell Fuelsave Diesel"

New standard fuels from Shell, designed to give you one litre "extra" range per tank at no extra cost.

http://www.shell.co.uk/home/content/gbr/products_services/on_the_road/fuels/fuelsave/unleaded/

Sounds great, but if you assume an "average" 50 litre fuel tank, that works out at just 2% extra economy - or 0.8mpg extra in a 40 mpg car.

(or it means you can pay 2p per litre more for decent Shell petrol rather than buying supermarket fuel, and the extra economy means that you're actually paying less over all....)

The above all assumes of course that you do get the extra 2% economy out of your car when you use the fuel.

Be interesting to see how it delivers, but you're going to have to track your fuel usage and costs very accurately to provide any figures accurate enough to draw a proper coclusion.

Still, as my local garage is Shell and its always the cheapest in the area (2p cheaper than Tesco this week...), I'll just use it anyway and see what it does.

Share this post


Link to post
Share on other sites

Gah, I wish you had a diesel car :P

I just stuck some V-Power diesel in my Yaris and noticed this new Shell 'fuelsave' stuff; Started a new thread for no real reason! :lol:

It'll be interesting to see whether it'd be a good substitute for those of us that use V-Power just to clean out the engine once in a while, esp. since it's a darn lot cheaper than V-Power!

It's still 4p more than sainsburys tho', so that projected save-1-litre-in-50 would still mean I'm worse off if I made it my primary fuel :(

It's not GTL tho', so I wouldn't get the extra power and smooth engine sound that V-Power gives, but then again I won't get the nasty mpg loss and loss of low-end torque either :)

Anyone who has injector and EGR clogging problems want to do a long-term test for us? :D

Share this post


Link to post
Share on other sites

Being a loyalist to Shell forecourts I also noticed their new FuelSave Unleaded and Diesel advertised. My Yaris now has a full tank of unleaded in it. Time will tell whether or not it is an improvement over the old standard unleaded.

alfiejts it must be a Shell versus Tesco thing going on; nearly all the Shell garages around the areas I normally drive are cheaper than the Tesco ones, not that I fancied feeding my Yaris on the cheap stuff supplied by my former employer, my first car (a Starlet) usually felt flat on Tesco fuel. Though I regularly gave that car little bottles of Redex that didn't half give it a kick.

I've tried a tank of V-Power unleaded after going 'why not' to a Shell coupon I recieved with my Shell swipe card and have to say V-Power doesn't make any noticeable difference with my light-footed driving style - and I'm normally good at noticing things. I constantly keep an eye on my fuel consumption figures alongside each 'tank mileage' and they were no different to regular Shell unleaded. Even moments that demanded more throttle and high revs didn't feel any different.

If my car can hold an average of more than 54mpg over a tankful and cover more than 465 miles, I will label that an improvement . .

Share this post


Link to post
Share on other sites

Avanzato is spot on. The engine management system of the Yaris isn't designed to take advantage of higher octane fuels, so you will get absolutely no benefit in power or economy out of their use.

You only get the benefit with systems that detect the spark ignition "knocking" inside the engine and vary the ignition timing to get the most "advanced" ignition timing the fuel will take. Higher octane fuels will take an earlier ingition spark in the engine cycle, which is how they release their extra power and economy, but the Yaris engine management system isn't that sophisticated.

The Yaris ECU is simly fixed and assumes a single ignition timing map for a 95 RON fuel, which is the standard fuel in the UK.

That's not quite right. The petrol engined Yaris do have knock sensors (I can't think of an ECU controlled petrol engine that doesn't have a knock sensor) and the ECU can and does alter ignition timing as the engine is running. It's just that the ECU isn't programmed to take advantage of the higher octane fuel. Therefore it can't access an engine map that would advance the timing enough to make any difference and hence you don't notice any difference with the higher octane stuff

:thumbsup:

I agree, higher ron fuel allows a bigger window so to speak (as they take longer to burn), hence you can advance ignition timing.

Again not quite right. They don't take longer to burn; they resist self ignition better and hence you can advance the timing to increase combustion chamber pressure and gain more power for a given charge. Imagine you have a mixed charge in a combustion chamber and have just sparked the plug and lit the mix. If you could freeze time a moment after you ignited the fuel and look at it in cross section you'd see destinct areas in the chamber. You'd see one area of burnt charge nearest the spark plug, a flame front where the burning is actually happening and an area of unburnt charge ahead of this. If you let this carry on in slow motion you'd see the flame front moving forward into the unburnt charge and since everything is heating up the gas pressure in the chamber would start to increase (that's how an engine works). However ahead of the head from the hot burnt gas behind the flame front you also have radiant heat acting on the unburnt charge ahead of the flame front. As pressure and temperature increase the tendency for petrol/air mixes to self ignite increases until eventually it causes it to detonate.

If you use a low octane fuel this happens earlier (lower temperatures/pressures) than with a high octane fuel

To get the most out of the fuel you want the maximum burn rate to happen when the piston is on the downward stroke but it takes time for the flame front to develop so you light the charge before the piston gets to Top Dead Centre (TDC). However the earlier you light it (within reason) the better the conditions for knock to occur. Therefore if you can resist higher temperatures/pressures you can be more aggresive with ignition timing and you can get more power.

The way modern petrol engines work is that the ECU controls various tables of conditions and engine parameters required for them that it can access. This is the "map". In a petrol engine the ECU will move through advanced timing maps pulling the ignition timing earlier and earlier until knock is detected by the knock sensor. This then overrides the timing map and forces it to take a more retarded timing until the knock disappears. This ends up with the ECU balancing between the timing map and the knock sensor protecting the engine. If however the ECU doesn't have maps with advanced enough timing then the better fuels can't take advantage of it

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this